$CATEGORY: Science - Khan Academy/2.Acids, Bases and Salts/2.Acids, Bases and Salts--Understanding of Chemical properties of acids and basis

//Multiple Choice

What gas is released when metal carbonates react with acids?
{
~ Oxygen
~ Nitrogen
= Carbon dioxide
~ Hydrogen
}

What kind of reaction occurs between sodium carbonate and hydrochloric acid?
{
~ Combination reaction
~ Displacement reaction
~ Decomposition reaction
= Double displacement reaction
}

When sodium carbonate reacts with hydrochloric acid, what products are formed initially?
{
~ NaOH and CO₂
= NaCl and H₂CO₃
~ Na₂CO₃ and HCl
~ NaCl and H₂O
}

Which of the following is unstable and decomposes into water and carbon dioxide?
{
~ Calcium carbonate
~ Sodium chloride
= Carbonic acid (H₂CO₃)
~ Calcium hydroxide
}

What is the formula of calcium carbonate?
{
~ Ca(OH)₂
= CaCO₃
~ CaCl₂
~ CaHCO₃
}

What gas is responsible for turning lime water milky?
{
~ Hydrogen
~ Nitrogen
= Carbon dioxide
~ Oxygen
}

What happens when carbon dioxide is passed through lime water for a long time?
{
~ The solution remains milky
= The solution turns back to colourless
~ The solution turns blue
~ The solution evaporates
}

What product is responsible for the milky white colour of lime water when carbon dioxide is passed?
{
~ Calcium hydroxide
= Calcium carbonate
~ Calcium hydrogen carbonate
~ Sodium bicarbonate
}

What is the chemical formula of sodium bicarbonate?
{
= NaHCO₃
~ Na₂CO₃
~ NaOH
~ NaCl
}

What test is used to confirm the presence of carbon dioxide gas?
{
~ Litmus test
~ Pop sound test
= Lime water test
~ Smell test
}

Which of these acids can react with sodium carbonate to release carbon dioxide?
{
~ Hydrochloric acid
~ Acetic acid
~ Sulfuric acid
= All of the above
}

What happens when calcium carbonate reacts with sulfuric acid?
{
~ It forms NaCl and H₂O
= It forms CaSO₄, H₂O, and CO₂
~ It forms CaO and H₂O
~ It does not react
}

What kind of solution is lime water?
{
= Dilute solution of calcium hydroxide
~ Dilute solution of calcium carbonate
~ Concentrated solution of NaOH
~ Acidic solution of HCl
}

//True or False

Carbon dioxide gas is colourless and odourless. {T}

Metal carbonates react with acids to release hydrogen gas. {F}

Carbonic acid (H₂CO₃) decomposes into water and carbon dioxide. {T}

Sodium bicarbonate is also called baking soda. {T}

Vinegar is an example of a base. {F}

Metal carbonates and bicarbonates release carbon dioxide when reacting with acids. {T}

Carbon dioxide turns lime water blue. {F}

Carbon dioxide is the only gas that turns lime water milky. {T}

//Fill in the blanks

Sodium carbonate reacts with HCl to form ________.
{
~ Na₂CO₃ and H₂O
= NaCl and H₂CO₃
~ NaCl and O₂
~ NaCl and H₂
}

The gas evolved when sodium bicarbonate reacts with vinegar is ________.
{
~ Oxygen
~ Hydrogen
= Carbon dioxide
~ Nitrogen
}

Excess carbon dioxide reacts with calcium carbonate to form ________.
{
~ Calcium chloride
~ Calcium hydroxide
= Calcium hydrogen carbonate
~ Calcium sulphate
}

The reaction of metal carbonates with acids produces salt, water, and ________.
{
~ Oxygen gas
~ Hydrogen gas
= Carbon dioxide gas
~ Nitrogen gas
}

The chemical formula for baking soda is ________.
{
~ Na₂CO₃
= NaHCO₃
~ CaCO₃
~ NaOH
}

The lime water test is used to identify ________.
{
~ Hydrogen gas
~ Oxygen gas
= Carbon dioxide gas
~ Nitrogen gas
}

//Numericals



//Match the following

Match the following items from Column A with their correct corresponding options from Column B\:
{
=Carbon dioxide gas -> Turns lime water milky
=Sodium bicarbonate -> Baking soda
=Calcium carbonate -> Evolves in Lime water test
=Vinegar -> Acid used in reaction
=Lime water -> Calcium hydroxide solution
=H₂CO₃ -> Decomposes into CO₂ and H₂O
=Na₂CO₃ + HCl -> NaCl + H₂O + CO₂
=Metal bicarbonates -> React with acids to release CO₂
=Calcium hydrogen carbonate -> Soluble in water
=Calcium hydroxide -> Used in whitewashing
}


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